Cooling help for ZX475Ti and 500.4 in Australia

winno · Post by **winno** » Wed Oct 28, 2009 11:22 pm

Hey everyone from Australia.

Just wondering if I can get some help here in regard to cooling my amps.

I have 3 Ti series amps installed in the boot/trunk of my Peugeot hatch; a 600.2 (at the rear between subs), a 500.4 and a ZX475Ti (behind rear seat).

They're installed under a false floor with fairly large vents directly above each amp (see pic) and mounted directly to the mdf floor. Each amp has it's own enclosure but there is a gap in the wall between the two hot amps which means that they kinda blow onto each other a bit.

The 600.2 is bridged to power the two Infinity VQ subs seeing a 2ohm load (and always stays cool to the touch), the ZX475 runs the Morel Elate mids (with two channels doing nothing right now) and the 500.4 runs the mids and tweeters.
It's an all active set up.

The issue is that the 500.4 and 475 both get very, very hot. Almost too hot to touch and they both shut off at the same time because of this after about an hour of playing. Even if only playing very quietly.

What can I do?
Can I change the fan direction on the amps by changing the polarity on the fan wires? I want to know if this is possible anyway on this these amps.
There's alot of very hot air inside the floor despite the big access holes.
Should I make the holes bigger to allow the side vents to vent more?
During the day the hatch shelf is in to keep the sun off but I still have the problem regardless (even when the shelf is off at night and allowing plenty of air to circulate).

Thanks for the help everyone.

Post by **ttocs** » Thu Oct 29, 2009 4:39 am

have you tried a little smoke, either from a cig or a incence stick to see where the air is going, and where it is not? I would not think it would be a big deal to switch the polarity as it is just a fan and should run backwards but that may not buy you anything if there is no air to move.

knightrider358 · Post by **knightrider358** » Thu Oct 29, 2009 4:40 am

Welcome to the forum, and thats a nice clean setup you got there. Now one question whats the rms signal voltage going into those amps and also is there something in between the 600.2 and the HU if so then thats amplifing the signal goin to the 600.2 and thats why its not getting hot cause its doesnt have to work as hard as the other 2 amps. Now if you amplified the signal going to the 500.4 and the 475 then the amps wouldnt have to work as hard. Try a TLD66 to amplify ur signal. Also if Im correct you said the amps are in an enclosure and they are vented from above. Well if there is anyway to open the sides of the enclosure open it and then install some cpu pans in a push and pull system. Also if you can go to a hardware store bouy some half inch or quarter inch spacing washers to have a gap between the amp and the mounting board to allow some air circulation to the bottom of the amps because the amps mosfets are mounted to the bottom plate of the amp for heat dissapation but how will dissapate heat if its mounted to a carpeted board. That board will act as an insulator if there is no air circulation to the bottom the the amp. Also you can cut a large square hole underneath the amps to allow the heated air to circulate underneath the whole rack but the amps will cover those large square holes and the naked eye wont see them. Well sorry this is long but I hope it give you some ideas. Again welcome to the forum.

winno · Post by **winno** » Thu Oct 29, 2009 1:04 pm

Thanks for the reply guys.
ttoc: that's what I thought but someone mentioned somewhere that the fans in these amps are DC brushless and because of this they may not be able to be made to change direction. I was thinking of simply flipping the fans over so that they blow out the top instead of sucking in there. Will see...

Will break out the incence and see where the smoke goes... Good suggestion.

kr358: The amps are all fed directly from a Clarion HX-D2 (up to 8V output). I'll check the levels on the outputs and inputs this weekend and see if I can get the amp input sensitivities adjusted down a bit. I don't even get to -15 on the head unit volume - it goes to 0dB and then on to about +10 I think so there's plenty more room to move here.

I was sourcing some spacers this weekend. The board they're screwed to is just mdf, painted black - no carpet inside at all as you can't see it anyway until I add the leds.

I had also thought about blocking off the gaps in the partial wall between the two hot amps so that they don't blow onto each other so much.

I'm trying to avoid adding additional fans at this stage...
Will keep you all posted.

Any other suggestions?

Cheers

Post by **ttocs** » Thu Oct 29, 2009 7:47 pm

I just moved to the midwest us from the desert of phoenix and was having temp problems as well. As he said if you can get the back plate of the amp a little bit off of the board it is mounted on that will help. I know that adding a line driver didn't help my temp problems as I am just not moving the air I needed to around the amp, and when it was moved it was normally above 90 degrees anyway and circulating hot air around your amps is not much good.

Post by **stipud** » Fri Oct 30, 2009 6:52 am

You've got the top vented properly from the looks of it, so the fans can blow air into the amp chassis. But from there, the air evacuates out the sides of the amp, and then what? It looks like you have no vent to push the air out from inside your amp rack. Unfortunately this means you are going to have to cut a hole and most likely add a fan to expel the hot air from underneath.

Post by **ttocs** » Fri Oct 30, 2009 1:53 pm

are the Ti amps different from the octane LE? My fans blow out towards me and suck in from the sides.

oldskoolmseriesfan · Post by **oldskoolmseriesfan** » Fri Oct 30, 2009 9:51 pm

Hey Tom, keep the Dutch gangsta avitar to your self, we cant handle that oldskool gangsta shat. Dont F with the Dutch!!!

Post by **ttocs** » Sat Oct 31, 2009 11:15 am

I had a thought about the brushless motor question and thought that the motors I use on my RC airplanes are brushless. I know for a fact that reversing the wires will make them run backwards and there is no difference for them........

winno · Post by **winno** » Sun Nov 01, 2009 1:53 am

ttocs wrote:I had a thought about the brushless motor question and thought that the motors I use on my RC airplanes are brushless. I know for a fact that reversing the wires will make them run backwards and there is no difference for them........

Well, the interesting thing is that today I took a fan out and wired it up in reverse and it didn't spin at all. It's the standard ADDA DC brushless fan that comes in these amps. Wired it back as it was first installed and no problem.

So I went about it another way...

I just flipped the fans over so they're now sucking in the side and blowing out the top. I have to contend with visible colour coded wiring normally hidden under a fan arm as I'd run out of black heat shrink but I'll tackle that another day.

I also reinstalled the amps on spacers about 2-3cm above the mounting board but I am unsure that this will do much as the output devices are not mounted directly to the chassis anyway.

I ran the system for about a 1/2hr pretty hard in the process of resetting all the gains (the head unit output is run much hotter now up near 0dB attenuation if I really want to hammer it) and also had a proper go at setting the phase of all the drivers too. The amps got warm but not anywhere near what they normally do after a serious listening session. Admittedly I only played the system for a short time so will have to see how I go after a longer play.

Incidently, the system has two other issues resolved through reinstalling the amps;
1. By finally running the correct phase on the drivers (tweets and mids which are on the dash facing up and the subs are run at 180 out with the midbases in the doors at normal phase), I get a much more palpable and solid front stage with my TA that is much wider and quite strikingly transparent.
2. A very bad turn off pop through the mids, midbases and subs is now completely gone.

If I have issues still I am thinking that the next step is to simply pull out the jigsaw and enlarge the top vents (just as well I hadn't had the grills for them made yet).

Will keep you all posted on the heat issue.

Post by **ttocs** » Sun Nov 01, 2009 6:07 am

if you look at the heatsinks for the output transistors, they are attached in a way that they do heat up the case as well. The top of my octane LE gets warm as well.

winno · Post by **winno** » Thu Nov 05, 2009 3:18 am

Well, the amps run for longer now but still get hot. Looks like I'll be breaking out the jigsaw for some bigger top vents.
I can't go extra fans as the boot is open to the cabin and even three fans is plainly audible on quieter passages.